Research On Inflow Performance Relationship Of Coalbed Methane Extraction

On the basis of the domestic and abroad literatures researches, the current key dynamic models of porosity and permeability were analyzed and compared; the differences between the coalbed methane reservoir and conventional gas reservoir in the geological cause and exploitation mechanism were also summarized; the processes of coalbed methane generation, diffusion and seepage were studied; then according to China's complex geological features , a suitable permeability model which could reflect the influences of changes in pore pressure and matrix shrinkage effects was selected; on the basis of previous studies on coal-bed methane, a three-dimensional, dual-porosity, two-phase, pseudo-steady, non-equilibrium sorption mathematical model was developed with the petroleum reservoir numerical simulation method. After that, this complex mathematical mode was approximated and solved by the finite-difference and a fully implicit method, then the source code was written. Furthermore,In application to the history matching for FZ318 well in Qinshui Basin, Shanxi province, the reliability and practicability of the model were verified. At the same time,the influences of various parameters on the IPR curves were analyzed at early stages of development. Finally, unique sets of gas production type curves for predicting and analyzing CBM production performance were established by using the program.